1. Field of the Invention
The present invention relates to a display board illuminated by a light source at the back side. More particularly the present invention defines to a display board which has uniform illumination.
2. Description of the Related Art
Display boards, such as a vehicular meter panel, can be illuminated in the dark by a light source at the back side. These boards have the problem of non-uniformity of illuminance depending upon distance from the light source. On solution to this problem has been to print black dots as am illuminance adjusting layer with their area increasing as they approach the light source on the back side of a light transmitting substrate, as disclosed in Japanese Patent Publication No. 53-2065.
However, in order to obtain the construction set forth above, after forming a colored translucent image layer on the surface of the light transmitting substrate, the substrate must be reversed in order to print and form the above-mentioned black dots, which complicates the manufacturing process.